There are mainly two sealing methods used in the carton packaging industry; namely hot melt (or cold glue) adhesive and pressure sensitive tape. Cold glue or hot melt systems can provide non-stop sealing operation as the adhesive supply tank can be replenished without stopping the machine which provides a significant advantage in reducing production down time. Down time in taping machines is in part determined by the size of the tape roll as the machine has to be stop periodically to replace a depleted tape roll with a new roll.
Regardless of this disadvantage, it is estimated that about 50% of case sealing operations use pressure sensitive tape, since it provides other benefits, such as low equipment capital cost; easy open and re-tape; dust-proof; etc. In general, tape is preferable particularly in the foods and pharmaceuticals industry.
In order to reduce the down time associated with carton taping, significantly larger diameter tape rolls are being produced to thereby increase tape length e.g. from 900 M (10″ diameter) to 2000 M (15″diameter) and when the large roll is used to effectively reduce the production down time by half.
U.S. Pat. No. 8,434,539 granted May 7, 2013 to Lam (the the disclosure of which is incorporated herein by reference) teaches a tape applicator which can be used to reduce the time required to change a tape roll by employing a removable insert with tape roll pre-installed the use of which can significantly reduce the time required to change a tape roll from about 1 minute as required for a conventional tape to about 15 seconds.
The tape applicator of the above referred to Lam patent works well with large tape roll (15″ diameter) but only for top sealing, since the tape roll is positioned above the tape applicator, or the machine frame. The bottom taper on the other hand based on current technology is limited to the smaller diameter tape rolls as the tape roll has to be installed below the tape head or below the machine frame.
Conventional case taping machines usually provide a top and a bottom cavity to mount the tape applicators, these cavities are normally approximately 18″ in length, 4″ in width. Both top and bottom mounting cavity are only slightly larger than the tape applicators to be received therein.
Machines are usually compactly built with limited conveyor length. For this reason the tape applicator of the above Lam patent can only be used when applying a bottom tape with the small diameter tape roll and thus a conventional applicator without an insert has been used in machines where the larger tape rolls are to be employed.